Process of producing hydrogen peroxid.



UNITED STATES P ENT OFFICE.-

RICHARD WOLFFENSTEIN, OF BERLIN, GERMANY.

PROCESS OF PRODUCING HYDROGEN PEROXID.

To all whom it may concern."

Be it known that I, RICHARD WoLrrENsTEIN, a subject of the Emperor of Germany, and a resident of Berlin, Germany, have invented-a new and useful Process of Producing Hydrogen Peroxid, of which the following is a specification.

The preparation of hydrogen peroxid by the action of carbonic acid on barium peroxid is described by Duprey Comptes Rendus, 55, 736 and by Balard, Zoe cit. 55, 738. According to the statements of these authors the process is carried out by adding barium peroxid in small duantities to water through which a rapid current of carbonic acid is passed so that Car 'boni'c acid is always in excess of the quantity of barium peroxid. The authors admit that by this process only a dilute solution of hydrogen peroxid can be obtained and that in order to obtain more concentrated solutions the barium carbonate which is formed must be filtered off and fresh quantities of barium peroxid added to the filtrate containing hydrogen peroxid. Repetition of these experiments confirms the statements of Duprey. For example: 100 grams of barium peroxid were introduced into 500 cc. of water through which a rapid cu'rrent of carbonic acid passed, the barium peroxid being added in portions ofabout 5 to 10 grams each, so that an excess of carbonic acid was always present. A't first a certain decomposition of the barium peroxid into hydrogen peroxid took" place, but this gradually diminished and finally ceased altogether; The experiment was stopped after about 21; hours-and a further passage of carbonic acid throughtho mixture had noeffect. On examination, the hydrogen pcroxid solution. thus formed decolorized 241. cc. of normal solution of potassium of permanganate while 100 grams of the barium peroxid'employcd was able to decolorize '10 cc. permanganate. In fact, examination of the precipitate containing the barium carbonate showed that it contained the greater part of the barium poroxid undecomposed, since on titration it still dccolorized more than 700 cc. normal potassium permanganate solution. The reaction was then-lore extreme] y incomplete only amounting to about 25 per cent. of the materialsemployed, so that this method cannot be employed for technical purposes. I

In my opinion the failure of thc Duprey method appears to be due to the formation,after a certain quantity of'barium peroxid has been added to the aqueous solution which is supersaturated with carbonic acid, of soluble barium bicarbonate, which reacts on meeting with fresh quantities of barium perspecification of Letters Patent.

Application filed June 15, 1906. Serial No. 321,847.

Patented Nov. 5, 1907.

oxid to form insoluble barium carbonate, which deposits upon and so closely envelops the barium peroxid that is not available to the action of fresh quantitics oi carbonic acid.

I have discovered that the conversion of barium per'oxid into hydrogen peroxid by means of carbonic acid takes place almost quantitatively if the barium peroxid and not the carbonic acid is maintained in excess. Under these conditions it was discovered that barium percarbonate forms which is a new compound and comparatively stable. Working under these conditions therefore no foreign substance is deposited upon distinguished from that of Duprey by being carried I out during the earlier stages in alkaline solution whereas according to the statements of Duprey the acid reaction of the carbonic acid prevails from the commence-- m'ent. i

The inost important condition to be observed in the manufacture of hydrogen peroxid through barium percarbonate, is that the solution should be at first maintained alkaline and all wed to become acid only, when the decomposition of the barium percarbonate into hydrogen pcroxid is ready to take place. The rate of introduction of the carbonic acid must therefore be regulated, and when working in extremely dilute'solutions, for instance, it is necessary to introduce the carbonic acid slowly because the water absorbs a certain quantity of carbonic acid and otherwise the mixture would acquire an acid reaction. On the other hand when working in concentrated solution, where the carbonic acid almost only comes into contact with the basic barium oxid or barium peroxid, the introduction may be rapid.

The following is an example of my process and oi the estimation tests at various stages thereof: 23'() grams barium poroxid suspended in 1(l0O cc. water is saturated with a strcain of carbonic acid. Samples were drawn at intervals of 5 minutes at the beginning and s'ubse quently every 10 minutes, The estimation of the hydrogen peroxid' contained in the solution was carried out by titration with decinormal potassium permanganate.

Beginning of the experiment:

5 12.00 o'clock 1 cc. solution 0,1 cc. 1/10 N. KM O 1205 1 0,1 t 1210 1 0,1 12.15 1 0,1 r 1220 l 0,15 l0 sl 1 il 44 u u H u v 1230 1 0,15 1235 1 .i 0,15 .i 1245 l 0,15 V 1255 1 u 0,15 a L05 072 1J5 1 u 03 i. L 1 1,9 7 L32 1 7,5 L45 1 13,7 u 1 u' u u ii is u 205 1 18,0 2J5 18,7

The technical advantage of working in alkaline solution according to this invention is that the conver- 25 sion of the barium peroxid into hydrogen peroxid takes stones in the form oi barium percarbonate than when con- .tained in the solution in a free state, as is the case where the solution is acid from the commencement of the 0peration.

I employ the expression barium peroxid herein broadly to include hydrated barium peroxid. 7

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. The process of producing hydrogen peroxid which consists in treating barium peroxid with carbonic acid; the treatment being commenced in alkaline solution and continued in acid solution.

2.. The process of producing:hydr0gen peroxid whiclr 40 .consists in causing a solution of carbonic acid tolreoct" upon barium peroxid; the latter 'being in excess during the first phase of the reaction and the former in excess I dnringii subsequent phzise. a

in testimony whereof, I have hereuntosigned my name in the presence of two subscribing Witnesses.

RICHARD WOLFFENS'lFliN.

' Witnesses:

l-InNnY HASPER,

- WoLDnMAR HAUET. 

